This application is based on Japanese Patent Application No. 11-207996 (1999) filed Jul. 22, 1999, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to an ink jet printing apparatus and an ink jet printing head.
2. Description of the Related Art
Recording apparatuses (printing apparatuses) for recording (printing) on recording media such as paper and sheets for OHP (hereinafter referred to as recording paper or simply as paper) are classified into the so-called serial type which uses a recording head mounted on a movable member (hereinafter referred to as a carriage) reciprocally moving in a direction (main scanning direction) perpendicular to a recording paper transporting direction and a line type which uses a recording head having recording elements arranged within a range corresponding to a width of the recording paper. These recording apparatuses use recording heads which are configured for various recording systems such as a wire dot recording system, a thermal recording system, a heat transfer recording system, an ink jet recording system and an electrophotographic recording system.
Furthermore, there are widely used electronic appliances or data processing systems equipped with these recording apparatuses, and apparatuses which are electrically connected to the recording apparatus by way of interfaces and provide commands related to edition and recording of data to be recorded with the recording apparatuses, and which constitute image data supply sources and may be computers as data processing apparatuses, image reading apparatuses or the like.
Out of the recording apparatuses mentioned above, ink jet recording apparatuses mostly comprise ink tanks for supplying ink as a recording agent and recording heads for ejecting supplied ink to the recording paper, and are generally configured to replace the ink tanks with others when the ink is consumed substantially in the ink tanks. In the recent years, there is used a construction using a recording head cartridge wherein an ink tank is integrated fixedly or detachably with a recording head thereby allowing the ink tank to be exchanged together with the recording head or to be detached from a recording head for exchanging, when the ink is consumed substantially in the ink tank.
Furthermore, there have been prevailing recording apparatuses which are capable of performing various printing works (for example, monochromatic and color printing works) while adequately exchanging recording heads or cartridges for different kinds of ink (for example, black ink and color ink) for optimum recording of data matched with kinds of data to be recorded, with compact constructions.
Out of the recording apparatuses which have the above described construction, a certain apparatus is configured to be capable of informing a user of data of a recording agent such as ink consumed as a recording work proceeds: a consumed amount of ink or an amount of ink held in an ink tank (residual amount of ink). Furthermore, a certain recording apparatus carries out the an operation to secure favorable recording condition (so-called ejection recovery operation) before starting a recording operation after recording agent supply means such as an ink tank or a recording head is exchanged.
Since the above-described ink jet recording apparatus is accompanied by a fear that it may wastefully consume the recording paper on which recording is interrupted when the printer can hardly continue a recording operation in the course of recording, it is preferable to stop the recording before the printer can hardly continue the recording operation actually and restart the recording operation after preliminarily obtaining a condition where the recording operation cannot be interrupted. Causes which make it hard to continue the recording operation in the course of recording are traced mostly to small residual amounts of ink. Accordingly, it is preferable to measure a residual amount of ink at times and provide warning when the residual amount is lowered to a predetermined level, thereby urging a user to replenish ink (exchange an ink tank or the like).
On the other hand, remarkable progresses have recently been made in photographic printers which provide images of the so-called photographic quality, and recording heads used for these printers have been configured acceleratedly for higher densities and smaller dots, whereby recording densities are now enhanced to 600 to 1200 DPI (dots/inch) and ink ejecting amounts are now reduced to 8 to 4 pl (picoliters). Such recording heads are apt to produce stripes, color ununiformities, textures and the like perceived by human eye on recorded images due to slight variations of ink ejecting characteristics from ejecting openings. Since the ejecting characteristics are varied and image qualities are degraded as the recording heads are used for a long time, the recording heads have image forming service lives shorter than conventional recording heads even when nozzles themselves including ink jet elements (heating elements of a recording head which use thermal energy for ejecting ink or piezoelectric elements of a recording head which use mechanical energy for ejecting ink) are free from uncorrectable problems.
The present invention has been achieved in view of points described above and has an object to adequately control variations of ejecting characteristics and dot forming locations on a recording medium (printing medium) due to a use history of a recording head (printing head), thereby making it possible to maintain a stable image quality for a long time.
In a first aspect of the present invention, there is provided an ink jet printing apparatus which carries out printing using a printing head for ejecting ink, comprising:
means for measuring data related to a use history of the printing head; and
means for controlling a timing of ink ejection from the printing head on the basis of the data related to the use history.
In a second aspect of the present invention, there is provided a printing method using a printing head for ejecting ink, comprising the steps of:
measuring data related to a use history of the printing head; and
controlling a timing of ink ejection from the printing head on the basis of the data related to the use history.
In the first or second aspect, the printing head may have ejection openings arranged in a plurality of columns in a direction different from a relative scanning direction to a printing medium, and the control means or step may control an ink ejection timing between the plurality of columns.
The first or second aspect of the present invention may further comprise means for or step of printing by bi-directionally scanning the printing head relative to a printing medium, and the control means or step may control an ink ejection timing in a forward direction relative to an ink ejection timing in a backward direction.
In the first or second aspect, the control means or step may control an amount of ink to be ejected by adjusting an energy of a drive signal to be applied to the printing head for ejecting the ink.
Here, the control means or step may adjust a width of the drive pulse to be applied to the printing head.
In the first or second aspect, the measuring means or step may have means for or step of counting the number of drive signals applied to the printing head for ejecting the ink.
Here, memory means may be comprised for accumulatively storing the number of the drive signals from the start of the initial use of the printing head as data related to the use history on the basis of measurements by the measuring means.
In the first aspect, the measuring means may have means for measuring a temperature of the printing head and a time elapsed at the temperature in conjunction with each other.
Here, memory means may be comprised for storing a temperature history from an operation start of the printing head as the data related to the use history on the basis of measurements by the measuring means.
In the first aspect, the measuring means may have means for counting the number of drive signals applied to the printing head for ejecting the ink, and means for measuring a temperature of the printing head and a time elapsed at the temperature in conjunction with each other; and
the control means, according to the data related to the use history on the basis of measurement by the measuring means, may control the timing of the ink ejection from the printing head and control an amount of the ink to be ejected by adjusting an energy of a drive signal to be applied to the printing head for ejecting the ink.
Here, memory means may be comprised for accumulatively storing the number of the drive signals from the start of the initial use of the printing head and a temperature history, as the data related to the use history on the basis of the measurements by the measuring means.
In a third aspect of the present invention, there is provided a printing head used for an ink jet printing apparatus having means for measuring data related to a use history of the printing head and means for controlling a timing of ink ejection from the printing head on the basis of the data related to the use history, the printing head being a form of a unit detachably mounted on the ink jet printing apparatus, the printing head comprising:
means for ejecting ink; and
means for storing data related to the use history on the basis of measurement by the measuring means.
Here, the ejecting means may have an electrothermal transducer for generating thermal energy to make the ink film-boil, as an energy used for ejecting the ink.
Incidentally, in this specification, the term xe2x80x9cprintxe2x80x9d (also referred to as xe2x80x9crecordxe2x80x9d) represents not only forming significant information, such as characters, graphic images or the like, but also represents forming images, patterns and the like on the printing medium irrespective of whether it is significant or not and whether the formed images are to be visually perceptible or not, in broad sense, and further includes the case where the medium is processed.
In addition, the term xe2x80x9cprinting mediumxe2x80x9d refers to paper for use in general printing apparatuses as well as a medium such as a cloth, a plastic film, and a metallic plate and the like and any substance which can receive inks ejected by the heads in broad sense.
Further, the term xe2x80x9cinkxe2x80x9d has to be understood in broad sense similarly to the definition of xe2x80x9cprintxe2x80x9d and should include any liquid to be used for formation of image patterns and the like or for processing of the printing medium.
Additionally, the term xe2x80x9cnozzlexe2x80x9d, as used hereafter, collectively refers to an ejection opening, a liquid passage in communication therewith, and an element for generating energy for use in ink ejection, unless otherwise specified.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.